This study is designed to show an absolute difference of 5% in 28-day mortality between colloids and crystalloids. Assuming a mortality rate of 20% in the crystalloids group, with alpha = 5% and beta = 10%, 1504 patients per treatment arm are needed. A total of 3010 patients will be enrolled. All randomised patients must be followed up (at least) till ICU discharge. One hundred active centres will be recruited in Europe. The participation of each centre will be around 3 to 6 months.